1. Technical Field
The following description relates to one or more techniques to correct an image forming property of an image forming device.
2. Related Art
An image forming device such as a color laser printer has been known, which includes a plurality of image forming units aligned along a sheet carrying belt such that toner images of respective different colors are sequentially transferred onto a sheet being conveyed on the sheet carrying belt by the image forming units. In such an image forming device, when the respective toner images are transferred into different positions on the sheet by the image forming units, a formed image becomes a low-quality one.
In order to secure the quality of the image, a technique referred to as registration to correct positional deviations between the toner images transferred onto the sheet has been employed (for example, see Japanese Patent Provisional Publication No. HEI8-118737). According to such a correction technique, a pattern including a plurality of marks is formed on a surface of the sheet carrying belt by each image forming unit, and the positional deviations between different color toner images are determined by detecting locations of the marks with an optical sensor. Then, based upon a result of the detection, the positional deviations between the toner images are corrected. Such positional deviation correction is performed prior to a printing operation, when a print request is received and it is determined that the positional deviation correction has to be executed.
Additionally, a similar technique has been known, in which a pattern for density correction is formed on a belt, a color density of the pattern is detected by an optical sensor, and based upon a result of the detection, a color density of an image to be formed is corrected.